A reflex arc is a neural pathway that causes an involuntary and immediate reaction to a stimulus, typically designed for protection.

1. Stimulus - heat from hot object
2. Receptor - temperature receptors in the finger detect the heat and generate nerve impulses
3. Sensory neurone - passes nerve impulses to a relay neurone, typically in the spinal cord
4. Relay neurone (intermediate neurone) - links sensory neurones to motor neurones
5. Motor neurone - passes nerve impulse from the relay neurones to effectors
6. Effector - muscle in the arm that can cause a response
7. Response - arm muscle contracts to move the hand away from the hot object

1. Involuntary - require no decision-making and prevent the brain being overloaded with stimulation
2. Protect the body from harm
3. Innate - effective from birth
4. Rapid

A withdrawal reflex is a type of reflex action where the body responds to danger by quickly moving away, such as pulling a hand away from a hot object.

An effector is the part of the body that carries out the response in a reflex arc, such as a muscle contracting.